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Okay I know it’s 15, simple math, after all 8+8 is 16, you would have to be an idiot not to know that, so it’s just 1 less than that, anyways let me pull out my calculator just to check…
oh i know that one from my cribbage days
15
MIT is this way.
i prefer Tallinna tehnikaülikool.
Why? Just take the time to do the work properly. You will get better at it, enjoy life more.
Some of us have aphantasia and can’t do maths in our head.
What does not being able to see inner images have to do with math?
I’m asking because I can’t see shit but I have no problems with doing math up to a certain point. Not in any way good at it but it doesn’t impair my memory to the point it would be a hindrance either.
Because you can’t hold two numbers in your mind simultaneously, or imagine one adding to another and the result of that. It’s probably difficult to explain if you are able to visualise things.
I can do maths on paper when I can see it on front of me. But I don’t have a mind’s eye.
I can’t see anything but I can still hold numbers (again, up to a point) in my head without any kind of problem. It’s not a memory impairment in any way, at least not for me. Then again there’s not that much research into it so I’m genuinely curious about your experience as well.
My thought exactly. I resonate with this meme but I also try to challenge myself to do math longhand on paper
I just say I’m not good at math while i look at someone in the eyes for a little while until they do the math.
I am an accountant, literally work all day with numbers. 8+7, fine, that’s 16 minus one or 14 plus one.
8x7? Never managed to memorize the times tables so that is, well 4 7s is 14 +14, that’s 28, so 8 7s is 28 + 28, which is 40 and 16 so that’s 56.
interesting how mathes works differently for many people. because I do 8+2 to get 10. then 7-2=5, so 10+5 = 15.
Neat. I just remember that 8 is 2 less than 10 and 7 is 3 less than ten, so you can either do 8-3+10 or 7-2+10. Both are 15. Its similar to how you do it but for some reason its easier for me this way.
Quick mafs
In high school calc, I would do all kinds of algebra, integration, etc. and then at the end add 8 and 7 and get 13. All the time.
Its like when you do the whole logic and calculations part and then forget to square root the number at the end.
I’d always forgot to change signs after multiplying
Must have been doing a lot of base-12 math?
To this day, put 7 anywhere in my equation and I am gonna return an error. Dunno why. Remove 7, I work, give me 7, I suddenly struggle a lot.
For me it’s 8+8-1 since the doubles are memorized
This is the same for me, but I did 7+7+1, basically
So, for me it is 10-8=2. Then 7-2=5. And then 10+5=15.
I don’t know what to make of this comments section. This many people really don’t have 8+7 down?
I don’t even feel superior about it, just bewildered.
For us older folk, and unfortunately, also for some younger folk that grew up in more “conservative” small towns, borrowing and fancy math trickery was the work of the devil.
We were required to memorize the addition tables as well as the multiplication tables. And even then, addition could be done on your fingers and toes so as long as you could add the big numbers like 8 & 7 together faster than the really slow kid could take off his shoes and work it the hard way, you were considered proficient at addition.
So ya, there’s a wide swath of America that just sucks at basic math.Yeah, I thought there was something more to it and am disappointed.
Maybe I just have it fresher in my head because I play a lot of Killer Sudoku. 15 pair box? That’s a 7-8 or a 6-9.
Same here. I wasn’t great before, but I’m actually super fast at anything below 45 now.
In my case, the mental math trick suggestion (make it 10 + 5) was intended as a way to build a skill using the provided, easy example. That type of mental math can be applied to much larger numbers, particularly when combined with other mental math tricks.
This is why learning binary is so important. In base two, the same equasion is 1000+0111=1111, now you just convert back to decimal with: 8+4+2+1= sweats and starts counting on fingers before reaching for calculator
Easy, just convert to hex, 0x0F
Neat trick, now do nonary!
Right, as we all know, the most sensible way to do nonary algebra is in ternary, so we simply calculate 22+21 and convert back to nonary, and optionally decimal afterwards. So, 2 add 1 is 0, carry the 1, add it to 2 for 10, add the 2, carry the one, pad to 4 places and we have 0120, or 16 in base 9. Now to convert to decimal… removes shoes and socks
None of y’all have ever played cribbage I see.
Came here to say this. This is easier that 2+2 tbh.
Mental math tricks are important.
Take 2 from the 7 and give it to the 8. You now have 10 + 5. Much easier math.
Take 2 from the 7
Hold on, I just need to check something. Looks around nervously
Yes, that seems easier to me as well! I was not allowed to do this according to the teacher when I was a child. They wanted me to do it in some weird counterintuitive way. But I was very stubborn and I am still doing calculations in this way. She is not the boss of the way I think!
8+7 = 8 + ( 2 + 5) = ( 8 + 2 ) + 5 = 10 + 5
Then just do the column addition (1 + 0) =1 and (0+5)=5
Thus concat(1,5) = 15
Now do it where you turn all the numbers into ones via math fuckery
8+7
11+1+1+1+1
that an 11
That would require me to make a +1 and a -1 table and I would have a real hard time knowing if I made the tables display correctly.
I once typed in 1+1, though it was several term equation and I was mentally reducing each term before punching it in.
When I’m doing woodworking and I need to add up some very simple measurements I always use a calculator. I could very easily do it in my head and often automatically do without even thinking about it. However I’ve learned the hard way it’s very easy to make a simple error with even something as simple as 8+7 and chances are you won’t find out till later when two parts don’t fit together. That’s 20 hours down the toilet, just because I didn’t double check using the shop calculator.
I’m alright when it comes to mathematics, but my memory is a swiss cheese. I’ll do a calculation, context switch and 3 seconds later it’s either gone or I remember incorrectly. Having things written down, on paper or in a calculator, gives peace of mind.
Totally this. Find an online calc that accepts fractions and just get it done right in a few seconds vs trying to convert to 16ths or some crap. Which is why I use all metric unless I’m forced into imperial units.
